Models for the Prediction of Transients in Closed Regenerative Gas Turbine Cycles With Centrifugal Impellers

2005 ◽  
Vol 127 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Theodosios Korakianitis ◽  
N. E. Vlachopoulos ◽  
D. Zou
Keyword(s):  
Gas Turbine ◽  
Transient Response ◽  
Transient Flow ◽  
Space Station ◽  
Turbine Engine ◽  
Physical Mechanisms ◽  
Disturbance Propagation ◽  
Solar Powered ◽  
Energy And Momentum ◽  
Component Models

This paper presents transient-flow component models for the prediction of the transient response of gas turbine cycles. The application is to predict the transient response of a small solar-powered regenerative gas-turbine engine with centrifugal impellers. The component sizes are similar to those under consideration for the solar-powered Space Station, but the models can easily be generalized for other applications with axial or mixed-flow turbomachinery. New component models for the prediction of the propagation of arbitrary transients in centrifugal impellers are developed. These are coupled with component models for the heat exchangers, receiver and radiator. The models are based on transient applications of the principles of conservation of mass, energy, and momentum. System transients driven by sinusoidal and double-step inputs in receiver salt temperature are presented and discussed. The new turbomachinery models and their coupling to the heat-exchanger models simulates disturbance-propagation in the components both upstream and downstream from the point of generation. This permits the study of the physical mechanisms of generation and propagation of higher-frequency contents in the response of the cycle.

scholarly journals Models for the Prediction of Transients in Closed Regenerative Gas-Turbine Cycles With Centrifugal Impellers

1994 ◽  
Author(s):  
T. Korakianitis ◽  
N. E. Vlachopoulos ◽  
D. Zou
Keyword(s):  
Gas Turbine ◽  
Transient Response ◽  
Transient Flow ◽  
Space Station ◽  
Turbine Engine ◽  
Physical Mechanisms ◽  
Disturbance Propagation ◽  
Solar Powered ◽  
Energy And Momentum ◽  
Component Models

This paper presents transient-flow component models for the prediction of the transient response of gas turbine cycles. The application is to predict the transient response of a small solar-powered regenerative gas-turbine engine with centrifugal impellers. The component sizes are similar to those under consideration for the solar-powered Space Station, but the models can easily be generalized for other applications with axial or mixed-flow turbomachinery. New component models for the prediction of the propagation of arbitrary transients in centrifugal impellers are developed. These are coupled with component models for the heat exchangers, receiver and radiator. The models are based on transient applications of the principles of conservation of mass, energy, and momentum. System transients driven by sinusoidal and double-step inputs in receiver salt temperature are presented and discussed. The new turbomachinery models and their coupling to the heat-exchanger models simulates disturbance-propagation in the components both upstream and downstream from the point of generation. This permitted the study of the physical mechanisms of generation and propagation of higher-frequency contents in the response of the cycle.

Prediction of the Transient Thermodynamic Response of a Closed-Cycle Regenerative Gas Turbine

2005 ◽  
Vol 127 (1) ◽  
pp. 57-64 ◽  
Author(s):  
T. Korakianitis ◽  
J. I. Hochstein ◽  
D. Zou
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Transient Response ◽  
Mass Flow ◽  
Flow Rate ◽  
Transient Flow ◽  
Closed Cycle ◽  
Flow Heat ◽  
Component Models

Instantaneous-response and transient-flow component models for the prediction of the transient response of gas turbine cycles are presented. The component models are based on applications of the principles of conservation of mass, energy, and momentum. The models are coupled to simulate the system transient thermodynamic behavior, and used to predict the transient response of a closed-cycle regenerative Brayton cycle. Various system transients are simulated using: the instantaneous-response turbomachinery models coupled with transient-flow heat-exchanger models; and transient-flow turbomachinery models coupled with transient-flow heat-exchanger models. The component sizes are comparable to those for a solar-powered Space Station (radial turbomachinery), but the models can easily be expanded to other applications with axial turbomachinery. An iterative scheme based on the principle of conservation of working-fluid mass in the system is used to compute the mass-flow rate at the solar-receiver inlet during the transients. In the process the mass-flow rate of every component at every time step is also computed. Representative results of different system models are compared and discussed.

scholarly journals Prediction of the Transient Thermodynamic Response of a Closed-Cycle Regenerative Gas Turbine

1993 ◽  
Author(s):  
T. Korakianitis ◽  
J. I. Hochstein ◽  
D. Zou
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Transient Response ◽  
Mass Flow ◽  
Flow Rate ◽  
Transient Flow ◽  
Closed Cycle ◽  
Flow Heat ◽  
Component Models

This paper presents instantaneous-response and transient-flow component models for the prediction of the transient response of gas turbine cycles. The component models are based on applications of the principles of conservation of mass, energy, and momentum. The models are coupled to simulate the system transient thermodynamic behavior, and used to predict the transient response of a closed-cycle regenerative Brayton cycle. Various system transients are simulated using: the instantaneous-response turbomachinery models coupled with transient-flow heat-exchanger models; and transient-flow turbomachinery models coupled with transient-flow heat-exchanger models. The component sizes are comparable to those under consideration for the solar-powered Space Station (radial turbomachinery), but the models can easily be expanded to other applications with axial turbomachinery. An iterative scheme based on the principle of conservation of working-fluid mass in the system is used to compute the mass-flow rate at the solar-receiver inlet during the transients. In the process the mass-flow rate of every component at every time step is also computed. Representative results of different system models are compared and discussed.

Investigation of the Transient Response of a Dual-Rotor System With Intershaft Squeeze Film Damper

1985 ◽  
Author(s):  
Qihan Li ◽  
James F. Hamilton
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Transient Response ◽  
Synthesis Method ◽  
Gas Turbine Engine ◽  
Rotor System ◽  
Squeeze Film ◽  
High Pressure Turbine ◽  
Turbine Engine ◽  
Squeeze Film Damper

A method is presented for calculating the dynamics of a dual-rotor gas turbine engine equipped with a flexible intershaft squeeze-film damper. The method is based on the functional expansion component synthesis method. The transient response of the rotor due to a suddenly applied unbalance in the high-pressure turbine under different steady-speed operations is calculated. The damping effects of the intershaft damper and stability of the rotor system are investigated.

Effect of Variable Guide Vanes and Natural Gas Hybridization for Accommodating Fluctuations in Solar Input to a Gas Turbine

2011 ◽  
Author(s):  
Kyle Kitzmiller ◽  
Fletcher Miller
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Gas Turbine Engine ◽  
Solar Thermal ◽  
Guide Vanes ◽  
Operational Strategies ◽  
Turbine Engine ◽  
Variable Nature ◽  
Wide Range ◽  
Solar Powered

In recent years, several prototype solar central receivers have been experimentally demonstrated to produce high temperature and high pressure gas capable of driving a gas turbine engine [1–4]. While these prototype receivers are generally small (< 1 MWth), advancements in this technology will allow for the development of solar powered gas turbine engines at a commercial level (sizes of at least several megawatts electric (MWe)). The current paper analyzes a recuperated solar powered gas turbine engine, and addresses engine considerations, such as material limitations, as well as the variable nature of solar input. In order to compensate for changes in solar input, two operational strategies are identified and analyzed. The first is hybridization, meaning the solar input is supplemented via the combustion of fossil fuels. Hybridization often allows for an increase in net power and efficiency by adding heat during periods of low solar thermal input. An alternative strategy is to make use of variable guide vanes on the compressor of the gas turbine engine, which schedule to change the air flow rate into the system. By altering the mass flow rate of air, and assuming a fixed level of heat addition, the operating temperature of the engine can be controlled to maximize power or efficiency. The paper examines how to combine hybridization with variable guide vane operation to optimize gas turbine performance over a wide range of solar thermal input, from zero to solar-only operation. A large material constraint is posed by the combustor, and to address this concern two alternative strategies — one employing a bypass valve and the other a combustor modified to allow higher temperature inlet air — are presented. Combustor modifications could include new materials and/or increased cooling air. The two strategies (bypass vs. no bypass) are compared on a thermodynamic basis. Finally, a yearly assessment of solar share and thermodynamic performance is presented for a 4.8 MWe gas turbine to identify the overall benefits of the operational strategies.

scholarly journals Computational Simulation of PT6A Gas Turbine Engine Operating with Different Blends of Biodiesel—A Transient-Response Analysis

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4258 ◽  
Author(s):  
Camilo Bayona-Roa ◽  
J.S. Solís-Chaves ◽  
Javier Bonilla ◽  
A.G. Rodriguez-Melendez ◽  
Diego Castellanos
Keyword(s):  
Gas Turbine ◽  
Transient Response ◽  
Structural Integrity ◽  
Computational Simulation ◽  
Numerical Procedure ◽  
Gas Turbine Engine ◽  
Response Analysis ◽  
Turbine Engine ◽  
Thermodynamic Variables ◽  
State Models

Instead of simplified steady-state models, with modern computers, one can solve the complete aero-thermodynamics happening in gas turbine engines. In the present article, we describe a mathematical model and numerical procedure to represent the transient response of a PT6A gas turbine engine operating at off-design conditions. The aero-thermal model consists of a set of algebraic and ordinary differential equations that arise from the application of the mass, linear momentum, angular momentum and energy balances in each engine’s component. The solution code has been developed in Matlab-Simulink® using a block-oriented approach. Transient simulations of the PT6A engine start-up have been carried out by changing the original Jet-A1 fuel with biodiesel blends. Time plots of the main thermodynamic variables are shown, especially those regarding the structural integrity of the burner. Numerical results have been validated against reported experimental measurements and GasTurb® simulations. The computer model has been capable to predict acceptable fuel blends, such that the real PT6A engine can be substituted to avoid the risk of damaging it.

Investigation of the Transient Response of a Dual-Rotor System With Intershaft Squeeze-Film Damper

1986 ◽  
Vol 108 (4) ◽  
pp. 613-618 ◽  
Author(s):  
Qihan Li ◽  
J. F. Hamilton
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Transient Response ◽  
Synthesis Method ◽  
Gas Turbine Engine ◽  
Rotor System ◽  
Squeeze Film ◽  
High Pressure Turbine ◽  
Turbine Engine ◽  
Squeeze Film Damper

A method is presented for calculating the dynamics of a dual-rotor gas turbine engine equipped with a flexible intershaft squeeze-film damper. The method is based on the functional expansion component synthesis method. The transient response of the rotor due to a suddenly applied imbalance in the high-pressure turbine under different steady-speed operations is calculated. The damping effects of the intershaft damper and stability of the rotor system are investigated.

Experimental Verification of a Digital Computer Simulation Method for Predicting Gas Turbine Dynamic Behaviour

1972 ◽  
Vol 186 (1) ◽  
pp. 323-329 ◽  
Author(s):  
A. J. Fawke ◽  
H. I. H. Saravanamuttoo ◽  
M. Holmes
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Gas Turbine ◽  
Transient Response ◽  
Digital Computer ◽  
Dynamic Behaviour ◽  
Simulation Method ◽  
General Purpose ◽  
Test Results ◽  
Turbine Engine

A mathematical model which simulates the transient response of a twin-spool gas turbine engine on a general purpose digital computer is described together with test results verifying the simulation.

Effect of Variable Guide Vanes and Natural Gas Hybridization for Accommodating Fluctuations in Solar Input to a Gas Turbine

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Kyle Kitzmiller ◽  
Fletcher Miller
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Gas Turbine Engine ◽  
Solar Thermal ◽  
Guide Vanes ◽  
Operational Strategies ◽  
Turbine Engine ◽  
Variable Nature ◽  
Thermodynamic Performance ◽  
Solar Powered

In recent years, several prototype solar central receivers have been experimentally demonstrated to produce high temperature and high pressure gas capable of driving a gas turbine engine. While these prototype receivers are generally small (<1 MWth), advancements in this technology will allow for the development of solar powered gas turbine engines at a commercial level (sizes of at least several megawatts electric (MWe)). The current paper analyzes a recuperated solar powered gas turbine engine, and addresses engine considerations, such as material limitations, as well as the variable nature of solar input. In order to compensate for changes in solar input, two operational strategies are identified and analyzed. The first is hybridization, meaning the solar input is supplemented via the combustion of fossil fuels. Hybridization often allows for an increase in net power and efficiency by adding heat during periods of low solar thermal input. An alternative strategy is to make use of variable guide vanes on the compressor of the gas turbine engine, which schedule to change the air flow rate into the system. By altering the mass flow rate of air, and assuming a fixed level of heat addition, the operating temperature of the engine can be controlled to maximize power or efficiency. The paper examines how to combine hybridization with variable guide vane operation to optimize gas turbine performance over a wide range of solar thermal input, from zero solar input to solar-only operation. A large material constraint is posed by the combustor, and to address this concern two alternative strategies—one employing a bypass valve and the other a combustor modified to allow higher temperature inlet air—are presented. Combustor modifications could include new materials and/or increased cooling air. The two strategies (bypass versus no bypass) are compared on a thermodynamic basis. It is found that it is possible to operate the gas turbine across the entire range without a significant drop in performance in either design through judicious adjustment of the vanes, though both approaches yield different results for certain ranges of solar input. Finally, a yearly assessment of solar share and thermodynamic performance is presented for a 4.3 MWe gas turbine to identify the overall benefits of the operational strategies. The annualized thermodynamic performance is not appreciably different for the two strategies, so that other factors such as mechanical design, operational issues, economics, etc. must be used to decide the optimal approach.

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